#include<iostream>
#include<algorithm>

using namespace std;

typedef long long LL;
const int N = 2e5 + 10;

LL n,c;

LL a[N];

int main()
{
	cin >> n >> c;
	for(int i = 1;i <= n;i++) cin >> a[i];
	
	
	sort(a + 1,a + n + 1);
	LL ret = 0;
	for(int i = 2;i <= n;i++)
	{
		//a[i]
		LL b = a[i] - c;
		ret += upper_bound(a+1,a+i,b) - lower_bound(a+1,a+i,b);
	}
	cout << ret << endl;
	
	
	return 0;
}
